st: RE: RE: efficiently creating 1/0 variables from existing string y/n variables

["Lachenbruch, Peter" <Peter.Lachenbruch@oregonstate.edu>]

Would you want to include an if `var'~="" in the encode statement?  You
still don't have 0 or 1.

Tony

Peter A. Lachenbruch
Department of Public Health
Oregon State University
Corvallis, OR 97330
Phone: 541-737-3832
FAX: 541-737-4001


-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Martin Weiss
Sent: Sunday, September 27, 2009 3:45 PM
To: statalist@hsphsun2.harvard.edu
Subject: st: RE: efficiently creating 1/0 variables from existing string
y/n variables


<>

-replace-ing these variables with numeric counterparts would require you
to
change the -type- from string to numeric as well. I think the best way
to do
this for many variables is to employ a loop over them, and have the old
ones
-drop-ped automatically...


**************
clear*

input  str1 alc_now   
 y
 y
 y
 y
 y
 y
 n 
 y          
end

clonevar alc_now1=alc_now
clonevar alc_now2=alc_now
clonevar alc_now3=alc_now

qui ds, has(type string)

foreach var in `r(varlist)'{
		encode `var', gen(`var'_new)
		drop `var'
}

list, noobs
**************


HTH
Martin


-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Michael
McCulloch
Sent: Montag, 28. September 2009 00:25
To: Statalist
Subject: st: efficiently creating 1/0 variables from existing string y/n
variables

Hello,
I have a long list of string variables which contain only "y", "n", or  
are missing.
I'm converting them to new numeric variables with values 1 if  the old  
variable is "y", and 0 if "n".
For example:
	gen etoh_now=alc_now=="y"

This gives, correctly:
.. list alc_now etoh_now, clean
        alc_now   etoh_now
   1.         y          1
   2.         y          1
   3.         y          1
   4.         y          1
   5.         y          1
   6.         y          1
   7.         n          0
   8.         y          1

Is there a more efficient way to do this, where I can change "y" to 1  
and "n" to 0 without creating a new variable and manually dropping the  
old variable?







Michael McCulloch, LAc MPH PhD
Pine Street Foundation
124 Pine Street
San Anselmo, CA 94960-2674
tel:	415-407-1357
fax: 	206-338-2391
mm@pinestreetfoundation.org






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